﻿using System.Collections.Generic;
using System.IO;
using Newtonsoft.Json;
using Newtonsoft.Json.Linq;
using System.Data;
using System.Reflection;
using System;

/// <summary>
/// Json帮助类
/// 使用前需引用开源项目类库：Newtonsoft.Json.dll
/// </summary>
public sealed class JsonHelper
{
    /// <summary>
    /// 将对象序列化为json格式
    /// </summary>
    /// <param name="obj">序列化对象</param>
    /// <returns>json字符串</returns>
    public static string SerializeObjct(object obj)
    {
        return JsonConvert.SerializeObject(obj);
    }
    /// <summary>
    /// 解析JSON字符串生成对象实体
    /// </summary>
    /// <typeparam name="T">实体类</typeparam>
    /// <param name="json">JSON字符串</param>
    /// <returns></returns>
    public static T JsonConvertObject<T>(string json)
    {
        return JsonConvert.DeserializeObject<T>(json);
    }
    /// <summary>
    /// 解析JSON字符串生成对象实体
    /// </summary>
    /// <typeparam name="T">对象类型</typeparam>
    /// <param name="json">json字符串</param>
    /// <returns></returns>
    public static T DeserializeJsonToObject<T>(string json) where T : class
    {
        JsonSerializer serializer = new JsonSerializer();
        StringReader sr = new StringReader(json);
        object obj = serializer.Deserialize(new JsonTextReader(sr), typeof(T));
        T t = obj as T;
        return t;
    }
    /// <summary>
    /// 解析JSON数组生成对象实体集合
    /// </summary>
    /// <typeparam name="T">对象类型</typeparam>
    /// <param name="json">json数组</param>
    /// <returns>对象实体集合</returns>
    public static List<T> DeserializeJsonToList<T>(string json) where T : class
    {
        JsonSerializer serializer = new JsonSerializer();
        StringReader sr = new StringReader(json);
        object obj = serializer.Deserialize(new JsonTextReader(sr), typeof(List<T>));
        List<T> list = obj as List<T>;
        return list;
    }
    /// <summary>
    /// 将JSON转数组
    /// 用法:jsonArr[0]["xxxx"]
    /// </summary>
    /// <param name="json">json字符串</param>
    /// <returns></returns>
    public static JArray GetToJsonList(string json)
    {
        JArray jsonArr = (JArray)JsonConvert.DeserializeObject(json);
        return jsonArr;
    }
    /// <summary>
    /// 将DataTable转换成实体类
    /// </summary>
    /// <typeparam name="T">实体类</typeparam>
    /// <param name="dt">DataTable</param>
    /// <returns></returns>
    public static List<T> DtConvertToModel<T>(DataTable dt) where T : new()
    {
        List<T> ts = new List<T>();
        foreach (DataRow dr in dt.Rows)
        {
            T t = new T();
            foreach (PropertyInfo pi in t.GetType().GetProperties())
            {
                if (dt.Columns.Contains(pi.Name))
                {
                    if (!pi.CanWrite) continue;
                    var value = dr[pi.Name];
                    if (value != DBNull.Value)
                    {
                        switch (pi.PropertyType.FullName)
                        {
                            case "System.Decimal":
                                pi.SetValue(t, decimal.Parse(value.ToString()), null);
                                break;
                            case "System.String":
                                pi.SetValue(t, value.ToString(), null);
                                break;
                            case "System.Int32":
                                pi.SetValue(t, int.Parse(value.ToString()), null);
                                break;
                            default:
                                pi.SetValue(t, value, null);
                                break;
                        }
                    }
                }
            }
            ts.Add(t);
        }
        return ts;
    }
}
